[0001] The present invention relates to a utility grid, and a method for controlling the
power generation in a utility grid.
[0002] Wind energy is often used to generate electrical power at power plants, often referred
to as wind farms, using, for example, the rotation of large wind turbines to drive
electrical generators. However, because wind speed and air density change over time,
power output from the generators of a wind farm may also change over time, sometimes
even falling to zero when wind speed drops below a minimum threshold. Variations in
power output from such wind farms may cause variations not only in an amount of power
flowing from the farm but also in the frequency of a power system to which the electrical
power is delivered for consumption thereof. A group of power systems, power plants,
and associated infrastructure spread over a geographical area is sometimes referred
to as a grid. A drop in power output from the wind farm can cause a deficiency in
power delivered to a local area of a grid of which the wind farm is within, as well
as power delivered to other areas of the grid. Typically, a power output of one or
more other power plants within the grid is adjusted to compensate for a change in
the power output from the wind farm. Accordingly, a size of the wind farm relative
to a local demand for power, sometimes referred to as a load demand, relative to a
load demand of other areas of the grid, and/or relative to an overall load demand
of the grid may influence the impact of the variable power output of the wind farm
on other plants in the grid. For example, when power output from the wind farm falls
to zero due to low wind, another plant within the grid may meet the total load demand
of a region of the grid local to the wind farm. Such other power plants are typically
plants that generate electrical power from coal, steam, a combustible fluid, water,
and/or solar energy but may also include, but are not limited to, gas turbine power
stations, nuclear power plants, or even other wind farms.
[0003] Typically, a grid includes a plurality of power generation systems which are spread
over a geographic area. The grid also includes systems that consume power (sometimes
referred to herein as "power systems") as well as infrastructure of the grid, such
as, but not limited to infrastructure for interconnection, control, maintenance, and/or
improvement of the power generation systems, the power systems, and/or any infrastructure
of the grid. For example, the grid may include electrical transmission lines interconnecting
the power generation systems, power systems within the grid, any infrastructure within
the grid, and/or any combination thereof. Typically, the grid includes a centralized
control system operatively connected to the power generation systems for controlling
a power output of each of the power generation systems, for example, using processing
logic. Typically, the centralized control system is operated by the network operator.
The power output of the power generation systems controlled by the centralized control
system may include, but is not limited to an amount of electrical power, a frequency
of electrical power generated, and/or a rate of change of the amount and/or the frequency
of electrical power.
[0004] The power generation systems may, for example, each serve a geographic region within
the grid by delivering electrical power to such regions. The power generation systems
may each include any type of power source. For example, the power generation system
may include a power source that generates electrical power at least partially from
coal, steam, water, a combustible fluid such as gasoline, natural gas, diesel fuel,
etc., and/or solar energy. Additionally, the power generation systems may include
a nuclear power source, a gas turbine power station, and/or a wind farm.
[0005] US 2002/084655 describes a system, method and computer program product for enhancing commercial
value of electrical power produced from a renewable energy power production facility.
[0006] In view of the above, a utility grid according to claim 1 is provided.
[0007] Further aspects, advantages and features of the present invention are apparent from
the dependent claims, the description and the accompanying drawings.
[0008] A full and enabling disclosure of embodiments of the present invention, provided
by way of example only including the best mode thereof, to one of ordinary skill in
the art, is set forth more particularly in the remainder of the specification, including
reference to the accompanying figures wherein:
Fig. 1 shows a schematic representation of a utility grid according to an embodiment
of the present invention.
Fig. 2 shows a schematic representation of a utility grid according to a further embodiment
of the present invention.
Fig. 3 shows a schematic representation of a utility grid according to another embodiment
of the present invention.
Fig. 4 shows a schematic representation of a utility grid according to an even further
embodiment of the present invention.
Fig. 5 shows a schematic representation of a utility grid according to still a further
embodiment of the present invention.
Fig. 6 shows a schematic representation of utility grid according to still a further
embodiment of the present invention.
Fig. 7 shows a schematic representation of a local controller according to an embodiment
of the present invention.
Fig. 8 shows a flow diagram according to an embodiment of the present invention.
Fig. 9 shows the variation of power output over time in a first condition when the
total output power is controlled with a method according to an embodiment of the present
invention.
Fig. 10 shows the variation of power output over time in a second condition when the
total output power is controlled with a method according to an embodiment of the present
invention.
[0009] Reference will now be made in detail to the various embodiments of the invention,
one or more examples of which are illustrated in the figures. Each example is provided
by way of explanation of the invention, and is not meant as a limitation of the invention.
For example, features illustrated or described as part of one embodiment can be used
on or in conjunction with other embodiments to yield yet a further embodiment. It
is intended that the present invention includes such modifications and variations.
[0010] Fig. 1 shows a schematic representation of a utility grid according to an embodiment
of the present invention. Therein, the utility grid 100 includes a centralized grid
control 110 which monitors and controls power production and power consumption within
the grid, grid frequency or the like. In Fig. 1, only part of the grid is shown in
detail while most of the network structure is schematically represented by reference
numeral 150. It will be understood by those skilled in the art that this part of the
grid may include a plurality of power lines, power generation systems, power consumers
and the like. However, the detailed structure of this part of the utility grid is
not essential for understanding the principles underlying the present invention and
has, therefore, been omitted.
[0011] Utility grid 100 further includes an intermittent renewable energy source 200. In
the embodiment of Fig. 1, intermittent renewable energy source 200 is shown as a plurality
of wind turbines 210, also called a wind park or a wind farm. However, it will be
understood by those skilled in the art that intermittent renewable energy source 200
may also include a single wind turbine 210 connected to grid 100 and/or a solar power
plant. In the following, the intermittent renewable energy source will be exemplified
by means of a wind power system without limiting the scope of the invention thereto.
It will be understood by those skilled in the art that any other
energy source exhibiting intermittent power generation behavior, i.e. a fluctuating
behavior that is non-dispatchable or only dispatchable to a small degree, may be used
as the intermittent power source without deviating from the scope of the present invention.
Further to wind power system 200, utility grid 100 includes a further power generation
system 300. The at least one further power generation system 300 may be any of a coal-fired
power plant, a steam plant, a combustible fluid plant, a hydropower plant, a gas turbine
power station, a biogas plant, a nuclear power plant or any other power generation
system. Further to power generation systems, in addition or alternatively a power
storage plant or device allowing for dispatchable power supply may be used as power
system 300. Furthermore, it will be understood by those skilled in the art that a
plurality of further power generation systems 300 may be provided instead of only
a single one without deviating from the scope of the present invention. Wind power
system 200 and the at least one further power generation system 300 are configured
to generate electrical power and are adapted for feeding said electrical power into
utility grid 100.
[0012] Furthermore, utility grid 100 includes a local controller 400 which is adapted to
control the total power output of wind power system 200 and the at least one further
power generation system 300 as is indicated by the arrows. Typically, local controller
400 is realized as a programmable microcontroller but may be alternatively realized
by any other suitable hardware or software solution, e.g. fixed logic control device
circuit. In contrast to centralized grid control 110, local controller is only adapted
to control its local power generation systems 200 and 300 but is not connected to
more remote areas of the grid. Furthermore, local controller is adapted to control
the total output power of wind power system 200 and the at least one further power
generation system 300 not being a wind power system. Thus, local controller 400 is
adapted to control the total amount of electrical power fed into utility grid 100
by wind power system 200 and further power plant 300. It will be understood by those
skilled in the art that the term "total power output" includes both active and reactive
power. Accordingly, centralized grid control 110 may also demand a certain amount
of reactive power flow to be provided by power generation systems 200 and 300. In
this event, local controller 400 adjusts the power generation systems 200, 300 to
provide a sufficient amount of reactive power flow. It will be further understood
by those skilled in the art that it is not required that local controller 400 itself
directly controls wind power system 200 and power plant 300. Rather, wind power system
200 and power plant 300 may have their own individual control systems like, e.g.,
a wind turbine controller. However, local controller 400 may command a specific output
power to each of wind power system 200 and power plant 300. Furthermore, local controller
400 is connected with centralized control 110. Centralized grid control 110 is adapted
to request a desired total output power of wind power system 200 and power plant 300
from local controller 400. However, centralized grid control 110 is not itself connected
to wind power system 200 and power plant 300. Accordingly, wind power system 200 and
power plant 300 are controlled only via local controller 400. Local controller 400
may be configured to accept real-time signals from centralized grid control 110. Thus,
local controller 400 may participate in dynamic dispatch and automatic generation
control (ACG), which is a standard-type function of dynamic regulation of the grid
frequency.
[0013] Thus, the application of one or more local controllers 400 facilitates control of
the utility grid 100. In particular, centralized grid control 110 can rely on the
demanded total power output which is provided due to the control of local controller
400. Typically, the power output of wind power system 200 will be highly fluctuating
due to varying wind speed or other reasons. If such a wind power system 200 is part
of the local power generation infrastructure, the feed-in power of this local power
generation infrastructure will also fluctuate due to the amount of fluctuating wind
power. However, local controller 400 controls the other, e.g. conventional, power
plants 300 in the local infrastructure so that the desired total output power is fed
into utility grid 100. Thus, the intermittent power source and the dispatchable power
source, e.g. a wind farm and a gas turbine, act like a single entity under the control
of local controller 400. For example, local controller 400 may be adapted to control
the total output power of wind power system 200 and power plant 300 to be substantially
constant, e.g. equal to the desired total power output requested by centralized control
110. In another embodiment, local controller 400 may be adapted to control the total
output power of wind power system 200 and power plant 300 to vary only within a predetermined
range, i.e. to stay within a predetermined band. For example, the range may be determined
by centralized control 110 and transmitted to local controller 400. In a further embodiment,
local controller 400 may be adapted to control the total output power of wind power
system 200 and power plant 300 to vary according to a predetermined schedule. For
example, the schedule may be determined by centralized control 110 and transmitted
to local controller 400. The schedule may take into account times of day of large
power consumption, e.g. mornings and lunch time, and times of low power consumption,
e.g. during nighttime. Due to the above control strategies that could be implemented
in local controller 400, the statistical probability of power generated by wind power
system 200 is considerably increased and may, for example, allow for permanent reduction
of fossil or nuclear power generation. Furthermore, stability problems of grid 100
during serious weather conditions, e.g. storms, can be reduced since wind power production
can be locally backed-up by power plant 300.
[0014] Typically, local controller 400 is a closed-loop regulator which controls the power
output at least partially based on at least one variable indicative of the present
condition of utility grid 100. Therefore, local controller 400 is typically connected
with at least one sensor for measuring at least one grid variable, so that control
can be at least partially based on the at least one grid variable measured by said
sensor. Typically, the at least one grid variable is selected from the group consisting
of: active power, reactive power, power output of intermittent renewable energy source,
power output of alternate power generation system, current, voltage, frequency, power
factor, rate of change of power. In the embodiment of Fig. 1, local controller 400
is connected with a sensor 410 for sensing the power output of wind power system 200,
a further sensor 411 for sensing the power output of power plant 300, and a sensor
412 for measuring grid frequency. However, it will be understood by those skilled
in the art that sensors 410, 411, 412 may measure one or more of any of the aforementioned
grid variables. Furthermore, local controller 400 may be provided with additional
grid sensors for measuring additional grid variables.
[0015] Fig. 2 shows a schematic representation of a utility grid 100 according to a further
embodiment of the present invention. The basic configuration of utility grid 100 is
similar to the grid shown in Fig. 1. However, local controller 400 is connected with
at least one sensor 420 indicative of at least one environmental condition. The local
controller 400 is adapted to control the total power output at least partially based
on the at least one environmental condition measured by sensor 420. Typical environmental
conditions monitored by sensor 420 include wind speed, air density, irradiance, atmospheric
turbulence, rain condition, snow condition, air temperature, and humidity. Accordingly,
sensor 420 may include an anemometer, an air densimeter, a hygrometer, a thermometer,
a rain sensor, a snow sensor, a turbulence sensor and the like. Since the power output
of wind power system 200 strongly depends on the environmental, in particular the
atmospheric conditions, the accuracy of control by local controller 400 can be improved
by taking into account the environmental conditions determining the power output of
wind power system 200. For example, local controller 400 may increase the power output
of power plant 300 if an anemometer 420 measures a decrease in wind speed. Thus, the
total power output of wind power system 200 and power plant 300 can be maintained
at a constant level although the output of wind power system 200 drops due to the
calm.
[0016] Fig. 3 shows a schematic representation of a utility grid according to another embodiment
of the present invention. The basic configuration of utility grid 100 is similar to
the grid shown in Fig. 1. However, local controller 400 is connected with at least
one forecasting means 430 providing at least one forecasting variable. Local controller
400 is adapted to control the total power output at least partially based on the at
least one forecasting variable provided by forecasting means 430. Typical forecasting
variables predicted by forecasting means 430 include a weather forecast, a storm warning,
wind speed, air density, irradiance, atmospheric turbulence, rain condition, snow
condition, air temperature, humidity, and a dispatch schedule. Accordingly, forecasting
means 430 may include a meteorological service. Thus, local controller 400 may anticipate
the future weather conditions at the wind power site 200 within a predetermined forecast
horizon. In particular, local controller 400 may determine a plurality of meteorological
scenarios weighted with different probabilities. Since the power output of wind power
system 200 strongly depends on the weather conditions at the wind power site, the
accuracy of control by local controller 400 can be improved by taking into account
future weather conditions governing the future power output of wind power system 200.
For example, forecast means 430 may report a storm warning for a storm occurring with
a probability of 95 % within the next 2 hours at the wind power site 200. Then, local
controller 400 may shut down wind turbines 210 in the wind farm before the storm arrives
at the wind farm site. Simultaneously, local controller 400 may increase the power
output of a conventional power plant 300. Thus, the total power output of wind power
system 200 and power plant 300 can be maintained at a constant level or, at least,
within a predetermined range although the output of wind power system 200 drops to
zero due to the turbine shut-down.
[0017] In still another embodiment shown in Fig. 4, local controller 400 is connected with
at least one economic efficiency means 435. Economic efficiency means 435 provides
at least one economic efficiency variable, which is typically selected from the group
consisting of: a cost of operation, a fuel price, a market price of electrical energy,
or a power transmission fee. The local controller 400 is adapted to control the total
power output at least partially based on the economic efficiency variable provided
by economic efficiency means 435. Thus, local controller 400 may decide to reduce/increase
or shut-down/start-up power generators also on the basis of economic factors. For
example, the fuel price for diesel may be higher than that for gas. In this event,
local controller 400 may decide to shut down a diesel engine instead of a gas turbine.
Furthermore, local controller 400 may decide to store energy instead of feeding it
into the grid if the current marketprice for electric power is not attractive. Finally,
it should be understood that economic information may be provided to local controller
400 either by a separate economic efficiency means 435 or via centralized grid control
110 (as indicated by the dashed line). Of course, profit can be increased by applying
also economic considerations to the operation of local controller 400.
[0018] In another embodiment shown in Fig. 7, a forecasting means 440 is integrated in local
controller 400. Integrated forecasting means 440 receives input from external sensors
and/or an external forecasting means 430. Integrated forecasting means 440 is adapted
to provide a forecast within a predetermined forecasting horizon as described above
based on the information received. Local controller 400 further includes a total power
output estimation means 450 adapted to estimate the total power output within the
predetermined forecasting horizon. For example, output estimation means 450 may simulate
the power output of wind power system 200 based on a weather forecast. Furthermore,
estimation means 450 may determine from the estimated power output whether a desired
total power output requested by centralized grid control 110 can be generated by wind
power system 200 and power plant 300 within the forecast horizon. Typically, local
controller 400 comprises also a reporting means 460 adapted to report to the centralized
grid control 110 whether or not the desired total power output can be generated within
the forecasting horizon. Furthermore, reporting means 460 is also adapted to report
the estimated total power output determined by estimation means 450 to centralized
grid control 110. Thus, the central grid control 110 is informed by local controller
400 of the prospective total power output and can schedule countermeasures if necessary.
For example, power production may be increased in another part of grid 150 if wind
power system 200 must be completely shut-down during a storm and power plant 300 has
not sufficient maximum power to maintain the desired total output power. Thus, the
accuracy of control by local controller 400 can be improved by taking into account
weather forecasts or other forecasts governing the future power output of wind power
system 200. Furthermore, also a dispatch schedule may be taken into account by forecasting
means 440 so that the power demand within a predetermined forecasting horizon is considered.
Also, this may improve the accuracy of control by local controller 400 since, for
example, grid frequency will drop when large loads or a large number of smaller loads
are connected to the grid within a short period of time. For example, there exists
a large power demand during morning hours and at lunch time whereas considerably less
power is demanded during nighttime.
[0019] Fig. 5 shows a schematic representation of a utility grid according to an even further
embodiment of the present invention. The basic configuration of utility grid 100 is
similar to the grid shown in Fig. 1 but local controller 400 is connected with a sensor
420 for environmental conditions, a forecasting means 430, and economic efficiency
means 435. Thus taking into account actual and future conditions for intermittent
renewable power generation as well as economic factors, the accuracy and efficiency
of control by local controller 400 can be further improved.
[0020] Fig. 6 shows a schematic representation of utility grid according to still a further
embodiment of the present invention. Therein, utility grid 100 includes several intermittent
power generation systems and alternate dispatchable power plants grouped into regional
clusters. The intermittent power generation systems and the other power plants are
connected to utility grid 100, e.g., by power lines. Furthermore, loads (not shown)
like factories, private households etc. are connected to the grid and are supplied
with electrical power therefrom. Each of the regional power production clusters is
controlled by a local controller 400 as described above. Furthermore, each of the
local controllers 400 is connected with centralized grid control 110. Thus, centralized
grid control 110 controls the power production within grid 100 via local controllers
400. Instead of directly controlling the wind farms and power plants, centralized
control 110 only sends requests for desired total power output to each of local controllers
400. Then, local controllers 400 have to provide the demanded power output or to report
that the requested power output cannot be provided due to weather conditions, weather
forecast etc. Optionally, local controllers 400 may provide an estimated power production
schedule to centralized control 110 so that centralized control 110 can take countermeasures
if one or more of local controllers 400 cannot provide their desired total power output.
Thus, utility grid 110 has a hierarchical structure which delegates the control and
stability of total power output to local controllers 400. Since the local controllers
400 can react to regional weather conditions and may even take into account weather
forecasts, the stability of the grid can be maintained even for high wind power grid
penetration.
[0021] Fig. 8 shows a flow diagram according to an embodiment of the present invention.
In a first step, a desired total power output is transmitted from a centralized grid
control center to a local controller. The desired total power output may be a constant
value or a range within the total output power may vary. Next, the power output of
the at least one wind power source and the at least one other power source is controlled
by the local controller so that the total power output of the at least one intermittent
power source and the at least one other power source is substantially equal to the
desired total power output. In this embodiment, electrical power is generated by at
least one wind power source and at least one other power source. In one embodiment,
the step of controlling the total power output includes estimating a total power production
within a predetermined forecast period, and determining whether said estimated total
power production is sufficient for providing the desired total power output within
said forecast period. If the desired total power output cannot be provided, this is
reported to the centralized grid control. Optionally, also the information that the
desired total output value can be generated may be reported to the centralized control.
According to a further embodiment, at least one forecasting variable is obtained,
and the total power output is estimated at least partially based on the at least one
forecasting variable. Typically, the forecasting variable includes a weather forecast,
a storm warning, wind speed, air density, atmospheric turbulence, rain condition,
snow condition, air temperature, humidity, or a dispatch schedule. In one even further
embodiment of the present invention, an estimated total power output schedule for
the forecast period is reported to the centralized control. Thus, the centralized
control can schedule power production within the grid.
[0022] Fig. 9 shows the variation of power output over time in a first condition when the
total output power is controlled with a method according to an embodiment of the present
invention. In the embodiment shown in Fig. 9, a desired total output power requested
by a centralized control is constant over time. However, wind speed has been fluctuating
so that the power output from a wind power system also fluctuated, accordingly. It
will be understood by those skilled in the art that there exists a maximum power output
of the wind power system so that the output power will never exceed this limit even
for higher wind speeds. Another power plant within the regional cluster is controlled
by a local controller to supplement the power production by the wind power system
so that a substantially constant total output power can be maintained. However, forecast
data suggest a calm within the near future so that average wind speed will decrease.
Therefore, also the estimated power output by the wind power system will decrease
according to the wind speed. As a result, the output power of the other power plant
must be increased to maintain the requested desired total output power. As can be
seen from Fig. 9, it is still possible to maintain the desired total output power
although the power output by the wind system decreases.
[0023] Fig. 10 shows the variation of power output over time in a second condition when
the total output power is controlled with a method according to an embodiment of the
present invention. Here, also a constant total output power is requested by the central
grid control. However, a storm warning is reported by the forecasting means, resulting
in a considerable increase of wind speed. The wind speeds during the storm will be
too high for the wind turbines to operate so that they have to be shut down before
the storm arrives at the wind power site. Accordingly, the estimated wind power output
drops to zero for this wind power site. Similar to the example shown in Fig. 9, the
power output of the other power plant is increased when the wind power output is reduced.
However, it is shown that even with maximum power output from the other power plant,
the desired total power output cannot be attained. Rather, the total output power
drops to the power output of the other power plant. Therefore, a power gap Δ between
the requested desired total power output and the actual possible output power during
the storm exists. This power gap Δ has to be closed by increased power production
of other power generation systems in the grid. However, due to the forecasting capability
of the local controller the power gap can be anticipated well ahead of time. Thus,
it is possible to increase power generation early enough even for slowly reacting
power plants like coal-fired plants.
[0024] It will be understood by those skilled in the art that the present invention increases
the statistical confidence in stability of wind power penetrated utility grids. Thus,
conventional nuclear and/or coal fired power plants may be reduced without jeopardizing
grid stability and/or sufficient power supply. Also, including weather forecasts and
actual weather conditions increases predictability of wind power production. The hierarchical
structure of the grid having local controllers increases reliability since control
is based on local and/or regional data. Furthermore, centralized grid control is facilitated
since it can be based on guaranteed local power output values while the details of
the control can be delegated to the local controllers.
[0025] This written description uses examples to disclose the invention, including the best
mode, and also to enable any person skilled in the art to make and use the invention.
While the invention has been described in terms of various specific embodiments, those
skilled in the art will recognize that the invention can be practiced with modification
within the scope of the claims. Especially, mutually non-exclusive features of the
embodiments described above may be combined with each other. In particular, wind power
systems and solar power systems may be synonymously used in the context of the present
invention as they both represent intermittent energy sources. The patentable scope
of the invention is defined by the claims, and may include other examples that occur
to those skilled in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ from the literal
language of the claims, or if they include equivalent structural elements with insubstantial
differences from the literal languages of the claims.
1. A utility grid (100), comprising
a centralized control means (110),
an intermittent renewable power source (200) for generating electrical power;
at least one further power generation system (300); and
at least one local controller (400) for controlling the total power output of said
intermittent renewable power source (200) and said at least one further power generation
system (300),
wherein the centralized control means (110) is connected with the at least one local
controller (400) and adapted to request a desired total power output from the local
controller (400), and wherein the centralized control means (110) is not itself connected
to the intermittent renewable power source (200) and the at least one further power
generation system (300),
wherein the at least one local controller participates in dynamic dispatch and automatic
generation control.
2. The utility grid according to claim 1, wherein the local controller (400) is adapted
for controlling the total power output to vary according to a schedule prescribed
by the centralized control means (110) and/or to be within a predetermined range and/or
to be substantially constant.
3. The utility grid according to claim 1 or 2, wherein the local controller (400) is
connected with at least one sensor (410) for measuring at least one grid variable,
wherein the local controller (400) is adapted to control the total power output at
least partially based on the at least one grid variable measured by said sensor (410,
411, 412), wherein the at least one grid variable is selected from the group consisting
of: active power, reactive power, power output of intermittent renewable power source,
power output of alternate power generation system, current, voltage, frequency, power
factor, rate of change of power; and/or wherein the local controller (400) is connected
with at least one sensor indicative of at least one environmental condition (420),
wherein the local controller (400) is adapted to control the total power output at
least partially based on the at least one environmental condition measured by said
sensor (420), wherein the at least one environmental condition is selected from the
group consisting of: wind speed, air density, irradiance, atmospheric turbulence,
rain condition, snow condition, air temperature, humidity; and/or wherein the local
controller (400) is connected with at least one economic efficiency means (435) providing
at least one economic efficiency variable selected from the group consisting of: a
cost of operation, a fuel price, a market price of electrical energy, a power transmission
fee, wherein the local controller (400) is adapted to control the total power output
at least partially based on the at least one economic efficiency variable provided
by said economic efficiency means (435).
4. The utility grid according to any of claims 1 to 3, wherein the local controller (400)
is connected with at least one forecasting means (430, 440) providing at least one
forecasting variable, wherein the local controller (400) is adapted to control the
total power output at least partially based on the at least one forecasting variable
provided by said forecasting means, wherein the at least one forecasting variable
is selected from the group consisting of: a weather forecast, a storm warning, wind
speed, air density, irradiance, atmospheric turbulence, rain condition, snow condition,
air temperature, humidity, a dispatch schedule.
5. The utility grid according to any of claims 1 to 4, wherein the local controller (400)
comprises a total power output estimation means (450) adapted to estimate the total
power output within a predetermined forecasting horizon.
6. The utility grid according to any of claims 1 to 5, wherein the local controller (400)
comprises a reporting means (460) adapted to report to the centralized control means
(110) whether a desired total power output can be generated by the at least one intermittent
renewable power source (200) and the at least one other power generation system (300)
and/or to report to the centralized control (110) the estimated total power output
within a predetermined forecasting horizon.
7. A method of controlling the power generation in a utility grid, comprising the steps
of:
transmitting a desired total power output from a centralized grid control center to
a local controller;
generating electrical power using at least one intermittent renewable power source;
generating electrical power using at least one other power source;
wherein the centralized control means is not itself connected to the at least one
intermittent renewable power source and the at least one other power source, and
controlling the power output of said at least one intermittent renewable power source
and said at least one other power source so that the total power output of the at
least one intermittent renewable power source and the at least one other power source
is substantially equal to the desired total power output;
wherein the at least one local controller participates in dynamic dispatch and automatic
generation control.
8. The method according to claim 7, further comprising the steps of:
estimating a total power production within a predetermined forecast period;
determining whether said estimated total power production is sufficient for providing
the desired total power output within said forecast period; and
if the desired total power output cannot be provided, reporting to the centralized
grid control that the total power output cannot be provided within the forecast period.
9. The method according to claim 8, wherein, in the estimation step, at least one forecasting
variable is obtained, and wherein the total power output is estimated at least partially
based on the at least one forecasting variable selected from the group consisting
of: a weather forecast, a storm warning, wind speed, air density, irradiance, atmospheric
turbulence, rain condition, snow condition, air temperature, humidity, a dispatch
schedule.
10. The method according to any of claims 8 or 9, wherein the reporting step comprises
providing to the centralized control an estimated total power output schedule for
the forecast period.
1. Energieversorgungsnetz (100), umfassend:
eine zentralisierte Steuereinrichtung (110),
eine intermittierende, erneuerbare Energiequelle (200) zum Erzeugen von elektrischer
Energie;
mindestens ein weiteres Stromerzeugungssystem (300); und
mindestens eine lokale Steuerung (400) zum Steuern der Gesamtleistungsabgabe der intermittierenden,
erneuerbaren Energiequelle (200) und des mindestens einen weiteren Stromerzeugungssystems
(300),
wobei die zentralisierte Steuereinrichtung (110) mit der mindestens einen lokalen
Steuerung (400) verbunden und dazu angepasst ist, eine gewünschte Gesamtleistungsabgabe
von der lokalen Steuerung (400) anzufordern, und wobei die zentralisierte Steuereinrichtung
(110) selbst nicht mit der intermittierenden, erneuerbaren Energiequelle (200) und
dem mindestens einen weiteren Stromerzeugungssystem (300) verbunden ist,
wobei die mindestens eine lokale Steuerung an einer dynamischen Lieferung und automatischen
Erzeugungssteuerung beteiligt ist.
2. Energieversorgungsnetz nach Anspruch 1, wobei die lokale Steuerung (400) dazu angepasst
ist, die Gesamtleistungsabgabe so zu steuern, dass sie gemäß einem durch die zentralisierte
Steuereinrichtung (110) vorgegebenen Zeitplan variiert wird und/oder innerhalb eines
vorbestimmten Bereichs liegt und/oder im Wesentlichen konstant ist.
3. Energieversorgungsnetz nach Anspruch 1 oder 2, wobei die lokale Steuerung (400) mit
mindestens einem Sensor (410) zum Messen mindestens einer Netzvariablen verbunden
ist, wobei die lokale Steuerung (400) dazu angepasst ist, die Gesamtleistungsabgabe
mindestens teilweise basierend auf der mindestens einen von dem Sensor (410, 411,
412) gemessenen Netzvariablen zu steuern, wobei die mindestens eine Netzvariable ausgewählt
ist aus der Gruppe bestehend aus: Wirkleistung, Blindleistung, Leistungsabgabe der
intermittierenden, erneuerbaren Energiequelle, Leistungsabgabe des alternativen Stromerzeugungssystems,
Strom, Spannung, Frequenz, Leistungsfaktor, Änderungsrate der Leistung; und/oder wobei
die lokale Steuerung (400) mit mindestens einem Sensor verbunden ist, der mindestens
eine Umgebungsbedingung (420) anzeigt, wobei die lokale Steuerung (400) dazu angepasst
ist, die Gesamtleistungsabgabe mindestens teilweise basierend auf der mindestens einen
vom dem Sensor (420) gemessenen Umgebungsbedingung zu steuern, wobei die mindestens
eine Umgebungsbedingung ausgewählt ist aus der Gruppe bestehend aus: Windgeschwindigkeit,
Luftdichte, Strahlungsstärke, atmosphärischer Turbulenz, Regenbedingung, Schneebedingung,
Lufttemperatur, Feuchtigkeit; und/oder wobei die lokale Steuerung (400) mit mindestens
einer Wirtschaftlichkeitseinrichtung (435) verbunden ist, die mindestens eine Wirtschaftlichkeitsvariable
bereitstellt, die ausgewählt ist aus der Gruppe bestehend aus: Betriebskosten, einem
Kraftstoffpreis, einem Marktpreis für elektrische Energie, einer Stromübertragungsgebühr,
wobei die lokale Steuerung (400) dazu angepasst ist, die Gesamtleistungsabgabe mindestens
teilweise basierend auf der mindestens einen Wirtschaftlichkeitsvariablen zu steuern,
die von der Wirtschaftlichkeitseinrichtung (435) bereitgestellt wird.
4. Energieversorgungsnetz nach einem der Ansprüche 1 bis 3, wobei die lokale Steuerung
(400) mit mindestens einer Prognoseeinrichtung (430, 440) verbunden ist, die mindestens
eine Prognosevariable bereitstellt, wobei die lokale Steuerung (400) dazu angepasst
ist, die Gesamtleistungsabgabe mindestens teilweise basierend auf der mindestens einen
von der Prognoseeinrichtung bereitgestellten Prognosevariablen zu steuern, wobei die
mindestens eine Prognosevariable ausgewählt ist aus der Gruppe bestehend aus: einer
Wettervorhersage, einer Sturmwarnung, Windgeschwindigkeit, Luftdichte, Strahlungsstärke,
atmosphärischer Turbulenz, Regenbedingung, Schneebedingung, Lufttemperatur, Feuchtigkeit,
einem Lieferplan.
5. Energieversorgungsnetz nach einem der Ansprüche 1 bis 4, wobei die lokale Steuerung
(400) eine Schätzeinrichtung (450) für die Gesamtleistung umfasst, die dazu angepasst
ist, die Gesamtleistungsabgabe innerhalb eines vorbestimmten Prognosehorizonts zu
schätzen.
6. Energieversorgungsnetz nach einem der Ansprüche 1 bis 5, wobei die lokale Steuerung
(400) eine Meldeeinrichtung (460) umfasst, die dazu angepasst ist, der zentralisierten
Steuereinrichtung (110) zu melden, ob eine gewünschte Gesamtleistungsabgabe durch
die mindestens eine intermittierende, erneuerbare Energiequelle (200) und das mindestens
eine andere Stromerzeugungssystem (300) erzeugt werden kann und/oder um der zentralisierten
Steuereinrichtung (110) die geschätzte Gesamtleistungsabgabe innerhalb eines vorbestimmten
Prognosehorizonts zu melden.
7. Verfahren zum Steuern der Stromerzeugung in einem Energieversorgungsnetz, umfassend
die Schritte:
Übertragen einer gewünschten Gesamtleistungsabgabe von einer zentralisierten Netzleitstelle
an eine lokale Steuerung;
Erzeugen von elektrischer Energie unter Verwendung mindestens einer intermittierenden
erneuerbaren Energiequelle;
Erzeugen von elektrischer Energie unter Verwendung mindestens einer anderen Energiequelle;
wobei die zentralisierte Steuereinrichtung selbst nicht mit der mindestens einen intermittierenden,
erneuerbaren Energiequelle und der mindestens einen anderen Energiequelle verbunden
ist, und
Steuern der Leistungsabgabe der mindestens einen intermittierenden, erneuerbaren Energiequelle
und der mindestens einen anderen Energiequelle, sodass die Gesamtleistungsabgabe der
mindestens einen intermittierenden, erneuerbaren Energiequelle und der mindestens
einen anderen Energiequelle im Wesentlichen gleich der gewünschten Gesamtleistungsabgabe
ist;
wobei die mindestens eine lokale Steuerung an einer dynamischen Lieferung und automatischen
Erzeugungssteuerung beteiligt ist.
8. Verfahren nach Anspruch 7, ferner umfassend die Schritte:
Schätzen einer Gesamtstromproduktion innerhalb eines vorgegebenen Prognosezeitraums;
Bestimmen, ob die geschätzte Gesamtleistungsproduktion ausreichend ist, um die gewünschte
Gesamtleistungsabgabe innerhalb des Prognosezeitraums bereitzustellen; und
wenn die gewünschte Gesamtleistungsabgabe nicht bereitgestellt werden kann, Melden
an die zentralisierte Netzsteuerung, dass die Gesamtleistungsabgabe nicht innerhalb
des Prognosezeitraums bereitgestellt werden kann.
9. Verfahren nach Anspruch 8, wobei im Schätzschritt mindestens eine Prognosevariable
erhalten wird und wobei die Gesamtleistungsabgabe mindestens teilweise auf der Grundlage
der mindestens einen Prognosevariablen geschätzt wird, die ausgewählt ist aus der
Gruppe bestehend aus: einer Wettervorhersage, einer Sturmwarnung, Windgeschwindigkeit,
Luftdichte, Strahlungsstärke, atmosphärischer Turbulenz, Regenbedingung, Schneebedingung,
Lufttemperatur, Feuchtigkeit, einem Dispositionsplan.
10. Verfahren nach einem der Ansprüche 8 oder 9, wobei der Meldeschritt das Bereitstellen
eines geschätzten Gesamtleistungsabgabeplans für den Prognosezeitraum an die zentralisierte
Steuerung umfasst.
1. Réseau électrique (100), comprenant
un moyen de commande centralisé (110),
une source d'énergie renouvelable intermittente (200) pour produire de l'énergie électrique
;
au moins un système supplémentaire de production d'énergie (300) ; et
au moins un dispositif de commande local (400) pour commander la production totale
d'énergie de ladite source d'énergie renouvelable intermittente (200) et dudit au
moins un système supplémentaire de production d'énergie (300),
dans lequel le moyen de commande centralisé (110) est connecté à l'au moins un dispositif
de commande local (400) et conçu pour demander une production totale d'énergie souhaitée
auprès du dispositif de commande local (400), et dans lequel le moyen de commande
centralisé (110) n'est pas lui-même connecté à la source d'énergie renouvelable intermittente
(200) et à l'au moins un système supplémentaire de production d'énergie (300),
dans lequel l'au moins un dispositif de commande local participe à la commande de
distribution dynamique et de production automatique.
2. Réseau électrique selon la revendication 1, dans lequel le dispositif de commande
local (400) est conçu pour commander la production totale d'énergie pour varier selon
une planification prescrite par le moyen de commande centralisé (110) et/ou pour se
situer dans une plage prédéterminée et/ou pour être sensiblement constante.
3. Réseau électrique selon la revendication 1 ou 2, dans lequel le dispositif de commande
local (400) est connecté à au moins un capteur (410) pour mesurer au moins une variable
de réseau, dans lequel le dispositif de commande local (400) est conçu pour commander
la production totale d'énergie au moins partiellement sur la base de l'au moins une
variable de réseau mesurée par ledit capteur (410, 411, 412), dans lequel l'au moins
une variable de réseau est choisie dans le groupe constitué de : puissance active,
puissance réactive, production d'énergie de la source d'énergie renouvelable intermittente,
production d'énergie du système de production d'énergie suppléant, courant, tension,
fréquence, facteur de puissance, taux de variation de puissance ; et/ou dans lequel
le dispositif de commande local (400) est connecté à au moins un capteur indiquant
au moins une condition environnementale (420), dans lequel le dispositif de commande
local (400) est conçu pour commander la production totale d'énergie au moins partiellement
sur la base de l'au moins une condition environnementale mesurée par ledit capteur
(420), dans lequel l'au moins une condition environnementale est choisie dans le groupe
constitué de : vitesse du vent, densité de l'air, exposition aux rayonnements, turbulence
atmosphérique, condition de pluie, condition de neige, température d'air, humidité
; et/ou dans lequel le dispositif de commande local (400) est connecté à au moins
un moyen d'efficacité économique (435) fournissant au moins une variable d'efficacité
économique choisie dans le groupe constitué de : un coût de fonctionnement, un prix
de combustible, un prix du marché d'énergie électrique, un coût de transmission d'énergie,
dans lequel le dispositif de commande local (400) est conçu pour commander la production
totale d'énergie au moins partiellement sur la base de l'au moins une variable d'efficacité
économique fournie par ledit moyen d'efficacité économique (435).
4. Réseau électrique selon l'une quelconque des revendications 1 à 3, dans lequel le
dispositif de commande local (400) est connecté à au moins un moyen de prévision (430,
440) fournissant au moins une variable de prévision, dans lequel le dispositif de
commande local (400) est conçu pour commander la production totale d'énergie au moins
partiellement sur la base de l'au moins une variable de prévision fournie par ledit
moyen de prévision, dans lequel l'au moins une variable de prévision est choisie dans
le groupe constitué de : une prévision météorologique, un avertissement de tempête,
la vitesse du vent, la densité de l'air, l'exposition aux rayonnements, une turbulence
atmosphérique, une condition de pluie, une condition de neige, une température d'air,
une humidité, une planification de distribution.
5. Réseau électrique selon l'une quelconque des revendications 1 à 4, dans lequel le
dispositif de commande local (400) comprend un moyen d'estimation de production totale
d'énergie (450) conçu pour estimer la production totale d'énergie au sein d'un horizon
de prévision prédéterminé.
6. Réseau électrique selon l'une quelconque des revendications 1 à 5, dans lequel le
dispositif de commande local (400) comprend un moyen de déclaration (460) conçu pour
déclarer au moyen de commande centralisé (110) si une production totale d'énergie
souhaitée peut être produite par l'au moins une source d'énergie renouvelable intermittente
(200) et l'au moins un autre système de production d'énergie (300) et/ou pour déclarer
à la commande centralisée (110) la production totale d'énergie estimée au sein d'un
horizon de prévision prédéterminé.
7. Procédé de commande de la production d'énergie dans un réseau électrique, comprenant
les étapes consistant à :
transmettre une production totale d'énergie souhaitée d'un centre de commande de réseau
centralisé à un dispositif de commande local ;
produire de l'énergie électrique en utilisant au moins une source d'énergie renouvelable
intermittente ;
produire de l'énergie électrique en utilisant au moins une autre source d'énergie
;
dans lequel le moyen de commande centralisé n'est pas lui-même connecté à l'au moins
une source d'énergie renouvelable intermittente et à l'au moins une autre source d'énergie,
et
commander la production d'énergie de ladite au moins une source d'énergie renouvelable
intermittente et de ladite au moins une autre source d'énergie de sorte que la production
totale d'énergie de l'au moins une source d'énergie renouvelable intermittente et
de l'au moins une autre source d'énergie est sensiblement égale à la production totale
d'énergie souhaitée ;
dans lequel l'au moins un dispositif de commande local participe à la commande de
distribution dynamique et de production automatique.
8. Procédé selon la revendication 7, comprenant en outre les étapes consistant à :
estimer une production totale d'énergie au sein d'une période de prévision prédéterminée
;
déterminer si ladite production totale d'énergie estimée est suffisante pour fournir
la production totale d'énergie souhaitée au sein de ladite période de prévision ;
et
si la production totale d'énergie souhaitée ne peut pas être fournie, déclarer à la
commande centralisée de réseau que la production totale d'énergie ne peut pas être
fournie au sein de la période de prévision.
9. Procédé selon la revendication 8, dans lequel, dans l'étape d'estimation, au moins
une variable de prévision est obtenue, et dans lequel la production totale d'énergie
est estimée au moins partiellement sur la base de l'au moins une variable de prévision
choisie dans le groupe constitué de : une prévision météorologique, un avertissement
de tempête, une vitesse du vent, une densité de l'air, une exposition aux rayonnements,
une turbulence atmosphérique, une condition de pluie, une condition de neige, une
température d'air, une humidité, une planification de distribution.
10. Procédé selon l'une quelconque des revendications 8 ou 9, dans lequel l'étape de déclaration
comprend la fourniture à la commande centralisée d'une planification estimée de production
totale d'énergie pour la période de prévision.